daemon-forward-lookup.diff

   1 This patch adds a forward lookup of any hostnames listed in the
   2 "hosts allow" or "hosts deny" daemon config options.  Based on
   3 a patch by Paul Williamson.
   4
   5 To use this patch, run these commands for a successful build:
   6
   7     patch -p1 <patches/daemon-forward-lookup.diff
   8     ./configure                         (optional if already run)
   9     make
  10
  11 based-on: 40afd365cc8ca968fd16e161d24df5b8a8a520cc
  12 diff --git a/access.c b/access.c
  13 --- a/access.c
  14 +++ b/access.c
  15 @@ -210,6 +210,42 @@ static int match_address(char *addr, char *tok)
  16         return ret;
  17  }
  18
  19 +static int match_hostlookup(char *addr, char *tok)
  20 +{
  21 +       struct hostent *hp = NULL;
  22 +       unsigned int i, len;
  23 +       char *p;
  24 +
  25 +       if ((p = strchr(tok,'/')) != NULL) {
  26 +               *p = '\0';
  27 +               len = p - tok;
  28 +       } else
  29 +               len = strlen(tok);
  30 +
  31 +       /* Fail quietly (hp left NULL) if tok is an address, not a hostname. */
  32 +#ifdef INET6
  33 +       if (strchr(tok, ':') != NULL) {
  34 +               ;
  35 +       } else
  36 +#endif
  37 +       if (strspn(tok, ".0123456789") != len)
  38 +               hp = gethostbyname(tok);
  39 +
  40 +       if (p)
  41 +               *p = '/';
  42 +
  43 +       if (!hp)
  44 +               return 0;
  45 +
  46 +       for (i = 0; hp->h_addr_list[i] != NULL; i++) {
  47 +               tok = inet_ntoa(*(struct in_addr*)(hp->h_addr_list[i]));
  48 +               if (match_address(addr, tok))
  49 +                       return 1;
  50 +       }
  51 +
  52 +       return 0;
  53 +}
  54 +
  55  static int access_match(char *list, char *addr, char *host)
  56  {
  57         char *tok;
  58 @@ -223,7 +259,7 @@ static int access_match(char *list, char *addr, char *host)
  59                 strlower(host);
  60
  61         for (tok = strtok(list2, " ,\t"); tok; tok = strtok(NULL, " ,\t")) {
  62 -               if (match_hostname(host, tok) || match_address(addr, tok)) {
  63 +               if (match_hostname(host, tok) || match_address(addr, tok) || match_hostlookup(addr, tok)) {
  64                         free(list2);
  65                         return 1;
  66                 }